Slide-rule.



PATENTBD FEB. 27, 1906. BQD. CUPPAGB.

SLIDE RULE.

APPLICATION FILED 14.13.31. 1904.

Wwnassas; \HvEm-oR.

and; MM fl q/ BENJAMIN DENVER COPPAGE, OF WILMINGTON, DELAWARE.

SLIDE-RULE.

Specification of Letters Patent.

Patented Feb. 27, 1906.

Application filed March 31, 1904. Serial No. 200,957.

Another obj ect is to so constructa'slide rule','

that its scales are protected from injury by soiled hands during operation, a further object being to so construct a slide-rule that its simplicity would make possible its universal use by salesmen, clerks, artisans, and school children, for whom the more complicated devices of the kind are impracticable, and a further object being to minimize the cost of'production of such instruments, (the whole cost of material and labor being perhaps no greater than the cost of an indicator or runner upon similar instruments now upon the market.)

- These objects I attain in the manner hereinafter set forth, reference bein had to the accompanying drawings, in whic Figure 1 is a perspective view of the whole instrument. Fig. 2 is a cross-section on line A B, showing the scales within the tube. Fig. 3 is a cross-section on line C D, showing the indicator upon the tube. I

Similar letters refer to similar parts throughout the several views.

The transparent tube 0., preferably made of glass, envelops the fixed scale a, made, referably, of white 0 aque material, such as firistol-board or cellu oid, with the scales printed or engraved thereon, said scale 0 being securely attached to the interior of tube a by glue or other suitable means. The sliding scalebismade,preferably, of white opaque material, such as bristol-board or celluloid, and folded in some such manner as shown to insure its sliding freely throu h tube a between the edges of fixed scale a, s iding scale b having its scale printed or engraved thereon. The sliding scale I) being engraved upon the chord of the missing are of fixed scale 0 avoids rubbing and consequent disfigurement of the graduations of said sliding scale which would result from continued sliding contact were it an arc coincident with the inside of tube a.

The tube a is provided at either end with flange g projecting at right angles to its axis, said flan es being made, preferably, of soft rubber 0% square or triangular form to prevent rolling of tube a to keep scale side of tube uppermost and to break the shock of a drop upona hard surface, such as a table or the floor.

The sliding scale I) may be provided with an internal strip of wood or other suitable material to strengthen said sliding scale, said strip (1 beingattached to scale b by glueor other equally effective way, as by clamping it in a folded strip of metal.

The triangular form of sliding scale I), as shown'in Fig. 2, is designed to secure the desired frictional fit within the tube a and to insure close contact of the graduated scale edges, which is so essential.

The indicator e is to be made of transparent material, such as celluloid, having a line h etched upon its surface, as shown, and fashioned preferably, as shown in Fig. 3, with clamping tension upon tube a, given by the riveting together of the ends of the indicator 6 by the eyelet f, thus securing the indicator at any point u on tube a without liability of accidental shifting. This form of indicator has proven a highly satisfactory arrange ment during more than a years daily use, comparing'very favorably with far more costly arrangements. It operates as follows: 'The indicator clamps the tube for about two hundred and seventy degrees, having a ortion concentric with the exterior of sai tube, from which extends tangential portions, which are offset, radial to said tube to receive an eyelet-rivet, which joins the ends together. By gras ing the eyelet between thumb and second the loop the riveted portion can be ressed toward the tube, causing the tangential portions to act as toggles, which force open the ortion of indicator" which grips the tube. he indicator can then be easily moved. Upon releasin the grasp of the fingers the indicator will e secure in any osition. The

er and placing first finger back of indicator may be made in the orm of a split a of transparent celluloid, secured around said tube by ineans of a rivet through extensions from tangential portions of said index.

3. In a slide-rule, a straight transparent cylindrical tube, fixed and sliding scales within said tube, elastic rubber guards on each end of said tube, to protect it from shock.

BENJAMIN DENVER COPPAGE.

Witnesses:

H. B. BRADFORD, REGINALD CONSTABLE. 

